The present invention relates to new 5-position-substituted 2-alkylamino-4-amino-1-alkylbenzene compounds and oxidation hair dye compositions or agents for dyeing hair based on the use of the new 5-position-substituted 2-alkylamino-4-amino-1-alkylbenzene compounds as coupler substances.
Oxidation hair dyes have attained substantial importance in hair dye practice. A hair dyeing mixture is produced by oxidative coupling of developer substance and coupler substance on the hair shaft. This leads to a very intensive hair dyeing with very good color fastness. Furthermore different color shades can be produced by combination of appropriate developer and coupler substances.
Advantageously 2,5-diaminotoluene, 1,4-diaminobenzene, 2-(2'-hydroxyethyl)-1,4-diaminobenzene, 4-aminophenol, 4-amino-2-aminomethylphenol and 4-amino-3-methylphenol and substituted 4,5-diaminopyrazoles can be used as developer substances.
m-phenylenediamine and its derivatives such as 2,4-diaminophenoxyethanol, 2-amino-4-(2'-hydroxyethyl)aminoanisole or pyridine derivatives such as 3,5-diamino-2,6-dimethoxypyridine as a blue coupler, 1-naphthol, m-aminophenol and its derivatives such as 2-amino-4-chloro-6-methylphenol, 5-amino-2-methylphenol, 4-amino-2-hydroxyphenoxyethanol, 4-amino-5-fluoro-2-hydroxytoluene and 4-amino-5-ethoxy-2-hydroxytoluene as red couplers and resorcin, 4-chlororesorcin, 4,6-dichlororesorcin, 2-methylresorcin, 4-hydroxy-1,2-methylenedioxybenzene, 4-(2'hydroxyethyl)amino-1,2-methylenedioxybenzene and 4-hydroxyindole as couplers for brown-blond shades are all advantageously useful as coupler substances.
Oxidation hair dyes which are used to dye human hair must meet numerous special requirements. They must be unobjectional in regard to their toxicological and dermatological properties and they must dye with the desired color intensity. Furthermore a satisfactory light fastness, permanent wave fastness, acid fastness and friction fastness is required for the desired hair dye compounds. In each case the hair dye compounds must be stable to light, friction and chemical agents over a period of at least 4 to 6 weeks. Also it is necessary that a broad palette of various color shades can be obtained by combination of appropriate coupler and developer substances.
The coupler substances currently used, particularly for providing red and blue color shades, however do not meet these requirements in a completely satisfactory manner. Similarly these substances do not have the best dermatological properties for many applications. It has thus been necessary to find additional coupler substances with improved dermatological and toxicological properties. Furthermore these compounds have disadvantageous stability problems, particularly a premature bleaching under the influence of light.
The 5-halogen-2,4-bis-(alkylamino)-1-alkylbenzene disclosed in German Laid-Open Patent Application DE-OS 42 06 416 shows no mutagenic effect in an Ames test, however the color intensity of the dyed hair obtained with this coupler substance is not always satisfactory because of its solubility.
The coupler substances 2,4-diamino-5-ethoxytoluene and 2,4-diamino-5-(2'-hydroxyethyl)oxytoluene described in German Laid-Open Patent Application DE-OS 36 22 784 have of course good toxicological properties, however they produce only weak dyed colors when used with developers such a p-aminophenol or its derivatives.
5-fluoro-2,4-diaminotoluene described in German Laid-Open Patent Application DE-OS 40 28 661 shows no mutagenic effect, however the stability of the hair colors produced with this coupler substance to light is not satisfactory.